Disrupting energy with building solar cladding for ~90% of all our energy at ~$0.02/kWh

Summary:

By covering all of the roofs and external walls of buildings with solar cells we can generate around 90% of our total energy needs at costs of $0.02/kWh and less. Combined with ~$0.02/kWh battery storage and backup generators this allows for year round grid independent electricity for less than $0.05/kWh. This dramatically reduces energy costs and increases energy resilience. It would effectively cost around $2 to fill up a car at home with electricity.

Solar and building cladding:

Solar modules have achieved a cost of around $0.10/W or ~$20/m2. This is less than the cost of many building cladding materials meaning that with full integration into the roofs and external walls of buildings the solar modules can effectively have almost zero cost. A simple example would be a low-cost glasshouse where all the glass was replaced by glass solar modules. More practically this requires the development of optimized solar cladding systems that are weatherproof, safe, shade tolerant, inexpensive to install and maintain, and able to achieve very high coverage ratios. Waterproof click-lock flooring is suggestive. A focus on balance of system costs is also needed, including associated power systems. Solar cladding avoids grid costs and a typical house might have over 50kW of installed solar capacity, which in most cases will provide excess power even during winter. At some cost in efficiency transparent window solar modules are possible as are colored solar cells which would enable different building colors and even mosaics. As solar costs have come down it has become desirable to cover all available surfaces with solar cells, optimizing around the limiting winter energy use case. Vertical surfaces can be more optimal for start and end of day and winter generation when the sun is at lower elevations. This reduces battery energy storage requirements, but in general it becomes economically favorable to just cover all available surfaces, including fences.   

Solar has the lowest cost:

Solar is now the lowest cost source of energy and this does not just apply to grid scale solar farms. Without subsidy, rooftop solar in Australia is now as low as $0.03/kWh USD. Solar is becoming economic even in locations like Seattle which receives a little over half the annual solar energy of the best solar climates. Doubling the size of a solar installation to compensate for a poor solar climate can still result in lower cost solar energy than alternate sources. Further, solar modules have reduced in cost by around 20% for every doubling in production volume and around 7% of global energy currently comes from solar. This suggests that solar module cost will halve again as solar comes to dominate our energy production. 

Solar can scale:

According to an NREL paper rooftop solar in the U.S. has an immense technical potential of 1,118 GW of installed capacity and 1,432 TWh of annual energy production, with residential rooftops accounting for approximately 65% of this. However, this assumes only 26% of available roof area for buildings under 5,000 ft2 is suitable for PV deployment and it excludes vertical surfaces. Maximum solar coverage of roofs and vertical surfaces in the U.S. can scale to around 7 TW, far beyond current rooftop solar and enough to cover around twice our current electricity needs. This is mostly colocated with the communities using the electricity, bypassing ~$0.08/kWh average grid distribution costs. Thus we can argue that solar cladding will become the dominant source of electricity generation, even in poor solar climates. Not only should solar energy be collocated with energy use so as to minimize distribution costs but we also want to avoid displacing farmland and natural habitat with solar farms. Beijing has already issued directives to this end and this will become of increasing concern elsewhere.

Batteries:

Batteries are also on a substantial cost reduction curve and are well suited to distributed use and building level integration. Large battery systems in China now cost as little as $65/kWh. This corresponds to around $0.02/kWh per discharge cycle. Like solar, the battery market is far from fully scaled and we can expect battery production to further increase by more than 10x which might correspond to a further halving in cost. There are also many new battery technologies that might enable much lower cost batteries. Further, electric vehicles which have relatively large battery systems may be used as supplemental batteries which might further reduce effective battery costs again. 

Backup generators:

There may still be circumstances, especially at higher latitudes, where there is insufficient solar energy to get through winter and other events. This can be solved by integrating a small backup generator into the building level solar and battery system, providing an on demand energy source and greatly increasing energy system resilience. Backup generators are already becoming a sunk cost for many with the need to survive extreme weather and wildfire events that can result in many day loss of grid supplied electricity. Electric vehicles that can be charged elsewhere, like at locations with excess solar energy, and hybrid vehicles present another interesting on demand and mobile electricity generation or supply option. It is interesting to note that the total installed power of internal combustion engines in automobiles is much greater than 10x our total electricity generation capacity. There are new solid state power generation technologies in development that could also solve this problem. For example, thermophotovoltaic efficiency of 44% was recently achieved at 1435℃. This enables a small high efficiency backup generator system that could be powered by the incineration of municipal and biomass waste. This can scale to provide all the needed on demand energy at very low-cost and it would be renewable and less than $0.05/kWh. Municipal waste generally has a negative cost and even biomass at around $50 per metric ton would cost around $0.01/kWh of thermal energy and $0.03/kWh of electrical energy (assuming ~33% conversion efficiency). Even high population density cities which push the limits of solar energy availability might effectively achieve energy self-sufficiency by these methods. High population density cities also tend to have high electricity distribution costs, increasing the incentive. This approach is also applicable to large industrial electricity users where electricity needs might exceed colocated solar capacity, for example, industrial plants and data centers. 

Off-grid living:

Solar cladding with integrated battery storage and backup generators producing year round electricity for less than $0.05/kWh directly to the customer will be highly disruptive. The electricity distribution grid, which averages around $0.08/kWh, with costs generally increasing with each passing year, could be disrupted in many cases. Grid defection is likely to become a reality. It would seem ill advised to expend large amounts of capital to upgrade the electricity grid. This capital would be far better spent on accelerating the scaling of solar cladding systems, which will greatly reduce energy costs and also greatly increase energy security. Large power generation systems that depend on grid distribution, like solar farms, wind, and nuclear, may also be ripe for disruption as even if they have zero generation cost grid distribution costs would make them uncompetitive with colocated solar cladding. Their survival might depend on colocation with large energy users such as industrial plants and data centers. Solar cladding will also lead to a substantial excess in solar capacity during the summer months. Australia is already experiencing substantial periods of negative electricity prices. There is an opportunity for new energy intensive technologies that can take advantage of very low-cost excess summer solar energy. Generally this favors low capital cost high power systems with less of an efficiency emphasis that can be economically used intermittently at low utilization factors.

Status:

We are not currently pursuing this technology but have a technology path that we would pursue if we had an appropriate partner for capital, manufacturing, and scaling. We would actively encourage others to pursue the development and commercialization of this technology as it would make the world a much better place.