PV Pointer: Three tactics for better solar designs under time of use rates

The promise of lower utility bills is a key motivator for most prospective solar customers, but time of use (TOU) rates — which charge different electricity prices depending on the time of day — add complexity to finding the best deal for the customer. Luckily, there are several strategies solar contractors can use to design the optimal PV system under specific TOU rates that will increase a customer’s solar savings and make your proposals more competitive.

olar design and financial analysis software

Solar design and financial analysis software example.

1. Start with integrated system design and financial analysis tools

One of the first considerations for finding the best design for TOU rates is to make sure you’re using software tools that will let you easily and accurately determine how different design choices will impact the financial returns of your project.

The structure of TOU rates varies, with important differences in the time periods when different pricing applies. TOU rates can be very favorable for solar customers if peak price hours coincide with when PV systems produce the most. In other cases, like when peak price hours occur in the evening, TOU rates can reduce solar savings.

To get an accurate understanding of your customer’s savings, your financial modeling tools must take into account how much the PV system will produce at different times, combined with the exact structure of your customer’s TOU rate. Beyond that, integrated solar design and financial analysis software will allow you to quickly see how system design changes or alternative utility rates affect project economics.

2. Get smart about post-solar rate choices

A second consideration for saving your customer the most money with their solar installation is to familiarize yourself with their utility rate choices and the financial implications of different rates. In some cases, the solar customer only has one potential rate that they are eligible for, but other times (like for some PG&E customers) there are multiple options. If your customer has a choice between rates, make sure to explore the financial implications of different options.

Choosing the best rate can significantly improve the economics of the project. In a case study of a solar design for a medium-sized office building in PG&E territory in California, Aurora Solar found that choosing a different post-solar rate resulted in over $42,000 in additional savings over the lifetime of the project. In addition to the increased savings making your proposal more compelling, this kind of expertise can distinguish your company in the sales process.

3. Explore alternative azimuths for your PV design

Finally, contractors can also experiment with different azimuths (orientations) to adjust the timing of some of the array’s production. For example, if a system is facing west, it may produce less overall but have more production later in the day. In cases where peak hours are late in the day, there may be times when this makes sense.

Again, using an integrated program for solar design and financial analysis makes assessing the merit of these kinds of design changes a lot easier because you’ll more easily be able to compare the value of the solar energy produced, overall system production and other financial metrics like payback period.

Even if TOU rates have not arrived in your area yet, they are likely to be more common in the future. Getting smart about how to maximize your customers’ savings under TOU rates can help you stay ahead of the curve.

— Solar Builder magazine

Micro Tiny Home is a Minimalist’s Dream

Italian architect and engineer Leonardo Di Chiara recently designed and built a prototype of a micro tiny home, which is seriously small yet still wonderfully functional.  The so-called aVOID tiny house measures just 96 sq ft (9 sq) and is easily towable.  Given its diminutive size, it also presents some unique downsizing solutions.

The home rests atop a double-axle trailer and has a wooden frame, metal cladding, and plenty of glazing. The interior is comprised of a single room and a bathroom. To make the most of the available space, most of the furniture is hidden inside the walls. The home features a Murphy-style single bed, which can be pulled down when needed, and stored away during the day. It can also be turned into a double bed. The dining table also features a pull down design and can easily be stowed away when not needed.  There is also a small, but functional kitchenette, which features a sink, a two-burner induction stove, and some shelving for storage.

The aVOID home also features a rooftop terrace which is accessible via a ladder.  It is great for lounging on sunny days.  The bathroom is tiny and features a shower, composting toilet and some storage space.

Di Chiara is still working on the home, and plans to install solar panels and a greywater system, which will make it independent of the grid. The home is currently on display at Berlin’s Bauhaus Archive Museum of Design, but DiChiara lives in it full time otherwise, with the goal of learning all he can about tiny house living. He says it’s not much different that living at home with his parents, in a small bedroom which must also serve many purposes as one grows up.

Tiny Home Design With a Hidden Bed

The tiny home builder Cubist Engineering, which is based in Greenwich, New York has created a very interesting tiny home, which has no standard bedroom. Instead, the bed is stowed away under the ceiling in the living room and lowered with the press of a button when needed.

The so-called Sturgis is a 21 ft (6.4 m)-long towable home, and despite its very small size it is quite spacious. Most of the space is gained by not having a standard bedroom, but the rest of the layout was also carefully planned with maximizing the available space in mind.

The Sturgis tiny home features a CLT (cross-laminated timber) structure, and has a cypress wood siding, which was treated by the Shou Sugi Ban method to preserve it and deter pests.  The home also features a fiberglass roof. The home has a total floor space of 170 sq ft (15.8 sq m) and much of it is taken up by the living area, which is equipped with a modular sofa, some cabinetry, and a coffee table.

The kitchenette is small but functional. It features a butcher block countertop, and a two-burner induction stove, while there is also enough space for a fridge and freezer. The bathroom is also quite small, but big enough for a shower, toilet and sink.

The Sturgis has no lofts, the queen-sized bed is simply lowered down by the flick of a switch when it is time for bed.  The mattress is supported by a steel frame, which is wrapped in maple.   According to Cubist Engineering, the bearing and railing system used to raise and lower the bed is the same one that is also used to load fuel rods in nuclear plants.

There is also a so-called “bonus space” in this tiny home, which was created by a raised space next to the living room. It can be used as a reading nook, or storage space and is big enough to store a motorcycle. It can also be used as a utility area, storage space, and more. This storage area can also be accessed from the outside via a gull-wing door that is operated by a remote control.

For power the tiny home uses a standard RV-style hookup, though a solar power system is an optional add-on to the basic version.  Other add-ons include a rainwater collection system, an exterior deck, a security package comprised of cameras and motion sensors, as well as a remote management system, which allows for controlling the lighting, etc. using a smartphone app.

The basic version of the Sturgis home without any add-ons costs $99,000. Apart from homes, the firm also offers different versions of this tiny dwelling, which are suitable as retail space, studios and more.

Holland to Get Its Own Vertical Forest

Stefano Boeri’s Bosco Verticale idea has really taken off. Now the city of Eindhoven, the Netherlands will get it’s own vertical forest tower.  Similar buildings have already been built in Paris, France and Lausanne, Switzerland. The tower in Holland will provide affordable inner-city social housing.

The so-called Trudo Vertical Forest will be 246 ft (75 m) tall and have 19 floors. The façade will feature 125 trees, 5,200 shrubs and more than 70 species of plants. These will help cleanse the air, improving its quality, as well as provide a pleasant environment to live in.

The basic design of this tower is different than the previous versions of Bosco Verticale.  The exterior is covered in concrete planters and terraces, which jut out from the sides.

The tower will feature 125 apartment units, intended for young people looking for an affordable place to live. Each apartment will have a balcony with one tree and 20 shrubs. The Stefano Boeri Architetti intends to prefabricate the sections needed to build this tower and then assemble them on site.

The project appears to still be in the planning stage at this time, and there is no information about when construction is set to begin, nor by when it will be finished. Although given the fact that this is a prefab building, it should be erected quickly.

Tiny Home – Micro Camper

Living in a 250 sq ft tiny home would be downsizing enough for most people, but Richard Ward of Terraform Tiny Homes from Dallas, Texas recently traded in this “mansion”, as he calls it, for an even smaller home. He spent the last four months traveling the country in this “mansion” and has now traded it in for a 54 sq ft micro camper.

The camper is called Terraform 3 and it was built atop a boat trailer. It can be expanded into a 120 sq ft home when stationary. Richard bought the trailer used for $175 off Craigslist.  The home itself was built out of 16-gauge, 1-inch square steel channel framing that was welded together. The structure is so sturdy that he could install a small rooftop deck, which is a very nice addition to the home. And this choice of framing also left more interior space to work with.

The interior is reminiscent of a large teardrop trailer, and features a bed, a desk, a sink, some storage, and a small toilet. There is also an outdoor shower and an outdoor kitchen, which is stored away for transport using a hinged door at the back of the home. Ward likes to do most things outdoors, hence his choice to incorporate so much of the outdoors into his new home.  The deck and outdoor kitchen are perfect for that.

This new home is also a lot more mobile than his previous, larger tiny home was.  Much of Terraform 3 was constructed and furnished using repurposed and recycled materials.  For example, it features a countertop made of wine corks, and the floor is covered with pages taken from a vintage 1940s book of drawings.

Terraform 3 is very small and most people probably couldn’t imagine downsizing to such a drastic degree. But then again, how much space do we really need to live comfortably?