According to the Carbon Leadership Forum’s Carbon Avoided Retrofit Estimator’s (CARE) website, “Renovating an existing structure typically has a much lower carbon footprint than building a new one because it reuses most of the carbon intensive parts of the building—the foundation, structure and building envelope.” Sylvan Court, which was originally constructed in 1964, recently underwent a renovation to upgrade the existing building instead of tearing it down; and also constructed a new building on the property’s former parking lot, doubling the amount of rentable housing units. While the original building doesn’t earn points on the new building’s checklist, their strategy was a great approach to minimizing their carbon impact, reduce waste, while still promoting urban density by constructing more units on the same lot.

The new building, a 20-unit apartment building, obtained a Built Green 4-Star certification on the 2017 multifamily checklist. The building was able to do so by claiming a variety of points throughout the checklist. Some of the highlight features utilized in the Built Green checklist to get the points were using drought-tolerant and native vegetation and low-flow plumbing fixtures to minimize the amount of water used on the property; BIBS insulation and a lower blower door score to keep energy costs down; low VOC paints, finishes, and interior products with indoor air-quality certifications to keeps tenants safe and healthy; and utilizing local and durable material to keep the building standing for a long time to come.

In addition to the variety of green features utilized by the construction team, the building offers bike storage with a repair station to incentivize tenants to ride their bikes or walk. The building is located within of the urban village zone and has a walkability score of 91. This in itself will help encourage more healthy living while reducing the need for a car.

Author: Nina Olivier, Built Green Coordinator

Installing a solar battery storage solution provides the greatest benefit to homeowners who live in areas that experience frequent power outages, where full-retail net metering isn’t offered, or where battery incentives are available.

When solar panels are paired with a home battery, the excess electricity goes into the battery instead of going to the grid. As a result, when the sun goes down and your panels aren’t producing electricity anymore, you can use the energy you have stored in your battery—instead of paying for electricity from the utility.

Investment Opportunities in Battery Systems

Given local proposed rate increases for utilities, solar PV systems and battery storage are becoming a more economically viable option. The style of battery greatly affects how the batteries are used and how long they last. Many factors contribute to variability in battery life including temperature, proper discharge and recharge, and optimal application usage.

Average household batteries cost anywhere from $4000 for a small 4kWh battery up to $15,000 or more for a large 13kWh battery depending on the type of battery, installation location, backup power requirements, and type of inverter used. To give some perspective, an average 3-bedroom home uses around 20kWh of electricity per day. However, a lot of this energy is used during daylight hours and could be directly powered by solar alone. Therefore, a moderately sized 10kWh battery would generally be large enough to cover the evening and overnight periods. However, every household is different, and usage patterns can vary greatly. For those that are more energy conscious and use efficient appliances, a smaller 6kWh battery may be suitable.

The payback period or return on investment (ROI) for most battery systems is around 7–10 years. It’s generally more cost-effective to install rooftop solar and run efficient appliances or heat hot water during the day rather than store excess energy in a battery. However, for some people, the value and security of having a reliable, sustainable power supply easily outweighs the cost.

The high cost of clearing trees, creating access roads, and building power poles can be prohibitive to getting power in remote locations. After recent grid events in Texas and California, the value of battery backup is harder to ignore. In states like Hawaii, residents are even required to store energy because there are restrictions in place that do not allow for the export of excess solar power to the grid.

Incentives and Financial Assistance for Washington State

Congress extended the federal solar tax credit (known as the ITC) for an additional two years. This means that you’ll receive a tax credit of 26% of your system’s cost in 2021 and 2022 and 22% in 2023. If the full value is not used within one year, the remainder will roll into the next year. Federal tax incentives can also be extended to home battery storage systems.

The 100% Clean Electricity Act passed in 2019 by the Washington State Legislature removes the sales tax for most typical residential solar energy systems and offers some sales tax relief for larger commercial scale systems. For the average customer, that means you save around 10 percent right off the bat.

In addition, the Rural Energy for America Program (REAP) provides grants and loans to farmers and rural businesses to help them purchase renewable energy systems and make energy efficiency improvements by paying up to 25 percent of the project.  To see all available renewable energy incentives available in your zip code please visit the Database of State Incentives for Renewables & Efficiency (DSIRE).

Leading Solar Energy Storage Batteries

Solar energy storage options have been rapidly evolving and improving over the last decade and are no longer limited to large, inefficient, and unattractive nickel-iron storage systems. Now sleek, sophisticated, high performing, and long-lasting storage options are readily available. Examples are listed below with typical prices (2021 retail prices).

Tesla

Since 2015, Tesla has been at the front of the pack in the production of dependable residential solar batteries. Their flagship model, the Tesla Powerwall, is pegged by critics to be the best in the range. The Powerwall is a stackable solar battery that has a capacity of 13.5 kWh and is enough for the average home’s energy needs. Tesla has developed its lithium-ion battery in partnership with Panasonic, and the resulting product is believed to be of very high quality. The cost of one battery unit is around $10,100.

LG

LG is one of Tesla’s main rivals in the solar battery market. It has a battery model called the LG Chem solar battery system. At 9.3 kWh, the LG Chem is a decent solar battery that should be able to power a home that does not have massive power-consuming machines. It is best suited for homes that are connected to a power utility grid. Including installation charges, the LG solar battery can cost between $11,000 and $13,000.

Sonnen

Sonnen is a fast-growing German company founded in 2010. It has a share in the European and American markets through a network of agents and installers. Sonnen’s Eco battery core unit has a small capacity of 4 kWh but can be stacked to 16 kWh. Smart software within the battery system stores data relating to your home’s energy needs. It then uses the information to provide you with a genuinely futuristic solar experience. With pre-installation costs of $9000, the Sonnen Eco is an expensive solar battery. However, each battery comes with a warranty of functioning at 70% of optimum levels for ten years, which is higher than that of competitors.

The following table shows other leading solar storage energy batteries currently available on the market:

Credit: Clean Energy Reviews

A&R Solar, a local solar installation company, explains that in addition to achieving energy independence and reducing your carbon footprint, solar is a wise investment with positive financial returns. A&R Solar recommends roof-top mounted grid tied solar coupled with a double Tesla Power Wall system for a typical single-family home.

The following are price estimates for a typical single-family home provided by A&R Solar using their recommended Tesla Power Wall or SolarEdge Energy Hub systems:

Credit: A&R Solar

Achieving Total Energy Independence and Resiliency

Solar PV plus batteries boosts a home’s resiliency to power outages where gird electricity may be off for a few hours or for several days. The battery provides the means to avoid the use of fossil fuel burning generators to power the home in the event of an outage. In addition, unlike generators, solar panels and battery storage systems don’t create noise and air pollution that will bother you or your neighbors. This is a unique benefit and is a great way for anyone who currently has a generator to update their system.

Learn more about how A&R Solar provides solar and storage to build a homes resiliency during an outage:

Batteries can be used to store solar energy and then allow the owner to utilize battery power at night or anytime to reduce the purchase of highest cost of peak power. Utilities often charge the highest per kWh rate for electricity used during the peak time of day or season. Battery power can also be used to keep the building’s total grid energy usage low over time to ensure the customer is paying for the lowest price in a tiered rate structure.

In a remote location, or any location that doesn’t have an electrical grid, the combination of solar PV and batteries can supply reliable ongoing electricity to power typical household functions. Unlike grid-tied solar systems, off-grid systems have no connection to the utility grid and must make all the electricity necessary to power the home.

Credit: Lopez Community Land Trust

The Path to Community Microgrids

To meet climate action goals, many large utilities are looking to generate more electric power through solar and wind. Currently there are challenges with large scale utility storage and energy transmission. Microgrids have been shown to alleviate these challenges through functioning like a smaller version of a larger traditional electrical grid powered by solar with battery storage systems. With the increased cost of traditional grid power generated from fossil fuels, many microgrids are switching to a combination of solar and battery storage to supply electricity that is cost effective and has environmental benefits.

They provide opportunities for optimal solar placement and scalability, as they do not need to be placed on home roofs—they can be installed on parking garages, open fields, etc.—reducing roof penetrations and complexity during roof repairs and replacements. Microgrids also achieve resiliency by islanding from the central grid during an outage. Community microgrids represent a new approach for designing and operating the electric grid that achieves a more sustainable, secure, and cost-effective energy system while providing indefinite, renewables-driven backup power for prioritized loads.

Further Reading:

Backup & Storage. Solar Washington.

Webinar Presentation: Battery Based Systems: Design Considerations for Washington Solar. Solar Washington.

Home Solar Battery Systems - Comparison and Costs. Clean Energy Reviews.

Solar Integration: Solar Energy and Storage Basics. Office of Energy Efficiency & Renewable Energy.

Fact Sheet | Energy Storage (2019). Environmental and Energy Study Institute.

Just north of the entrance to Seward Park, directly across from the water’s edge resides The Lake House. Built in 1919, the historical home was designed by renowned California-raised architect, Edwin Ivey, in the Spanish Eclectic style reminiscent of the homes found in Pasadena. A street-to-street lot, prime location, and a magical facade sparked the interest of the founders of Dwell Development (Dwell), Abbey and Anthony Maschmedt. For them, it was love at first sight. Their challenge was taking the sustainability practices they employ in new homes and implementing them in a home over a century old. It was a challenge they fully embraced when they devised their plan for The Lake House 2.0.

Dwell set out to do something extraordinary with this amazing parcel located on Lake Washington Boulevard South. Their job was to solve the puzzle of taking advantage of a unique development opportunity while maintaining the original integrity of the existing home—with a little over 20,000 square feet there were endless possibilities.

Fortunately, the existing home sat on the front portion of the lot with a massive grass front yard facing the lake. Behind the house, there was an existing carriage garage, that was originally intended for a vehicle and a caretaker. Beyond the garage was a large, landscaped yard that fronted 57th Avenue South. The site being street to street, provided room for development and design.

In most cases, similarly zoned sites would see the existing house demolished, then subdivided to create 3 new approximately 7,000-square-foot parcels, with 3 new single-family homes built. However, the Lake House was architecturally significant, and while it would take a lot of work to modernize it for another century of use, the Maschmedts knew that preservation had to be the goal. Then again part of modernization is also using resources more wisely, and land and housing are finite resources. So they had to also re-envision the site to maximize such valuable resources. Ultimately, they decided to preserve the Lake House with a new DADU and office, then subdividing it into two parcels to build a new single family home with an accessory dwelling unit. This increased the housing capacity of the site to 4 housing units.

Curve balls are expected when planning a project like this, but the Covid-19 pandemic presented unique challenges when it came to design decisions. During the pandemic Seattle Parks, which owns Lake Washington Boulevard, had decided to shut down the boulevard regularly to accommodate pedestrians, bikes, and strollers. Continual access from the back of the Lake House needed to be maintained, because there was a looming threat of a permanent shutdown of the boulevard to cars.

The biggest obstacle of the project would be updating the existing single-family home. Though Dwell is well-versed in sustainable new construction, historical restoration was not on their resume yet. They needed to balance preserving the amazing home, saving it from the landfill and maintaining its original charm and character, while updating and modernizing it to assure it met all the expected energy efficiency of a Dwell Development home. Ultimately, the goal was for The Lake House 2.0 to be Dwell’s first Net Zero Energy renovation.

Inclusive of the down-to-the-studs renovation of the existing home, the existing carriage garage was demolished and replaced with their first Net Zero Energy DADU. The DADU includes a 2-car garage that is accessed off of 57th Avenue South and serves as the new Dwell Development office headquarters. In addition, another first for Dwell, a Net Zero Energy Ready 5-Star Built Green single-family home with a legal AADU was built on the remaining portion of the parcel in the rear overlooking the main house and the lake.

Dwell applied all their standard, tried and true, sustainable systems and practices to the project. The existing house was stripped down to the studs, and a 1,500 sq ft addition was added to the back. Originally built with no insulation, they knew that proper insulation would be critical. After removing all the plaster and lathe, they added blown-in cellulose insulation. The exterior was also clad in a rain-screen Portland Cement Stucco, a cladding very unusual for the Northwest. The new stucco on the addition would need to match perfectly to blend old and new. No stone was left unturned in preservation. Existing millwork, windows, light fixtures, and doors were removed, stored, and eventually returned to their rooms. Their goal was to avoid waste and reuse as much of it as possible.

Heating and cooling and air quality are essential to a sustainable home. Anthony and Abbey called on trusted manufacturers, because they knew they couldn’t do it all alone. Partnerships were essential to the project. Mitsubishi and Panasonic lent Dwell their HVAC and fresh air consultants to design a new type of state-of-the-art heating/cooling and fresh air system. They also donated all the equipment towards this never-used-before system. The HVAC system features an ERV integrated into the ducted heat pump air handler to provide triple filtration and air scrubbing, maintaining premium fresh air and thermal comfort throughout the home.

The Lake House and its DADU is designed for a 16kW solar PV array that provides it a net positive energy balance. The solar PV will not only power the home and DADU, but also the swimming pool and an electric vehicle. The single family home is solar PV ready and includes two level II charging outlets for EVs.

The final results are something Dwell Development is very proud of. A feather in their cap and a homage to sustainability. Having completed a 5-Star Net Zero Energy Certified Built Green renovation, a 5-Star Net Zero Energy Certified Built DADU, and a 5-Star Built Green Net Zero Energy Ready Single-Family Residence with AADU simultaneously in one project, Anthony and Abbey Maschmedt of Dwell Development believe anything is possible when you set your mind to it. Lake House 2.0 is ready to roll into the next one hundred years.