Elon Musk Is Only Somewhat Right That Tesla’s Solar & Storage Can Scale To Rebuild Puerto Rico’s Grid
Puerto Rico suffered devastating losses due to Hurricane Maria. Along with a long list of other challenges, the hurricane destroyed the island’s antiquated generation, transmission, and distribution grids. In part, this is due to their dependence on low-resiliency fossil fuels.
This led to the governor of the territory responding with a tweet of his own suggesting he was very open to this. Whoever Scott Stapf is, excellent tweet.
How realistic is this? Can Tesla really rebuild Puerto Rico’s electrical supply system? The answer, as with anything complex, is mixed.
Many of the Indicators are Positive
Is Tesla able to provide a mixture of rooftop solar and utility-scale solar sufficient to provide for all of Puerto Rico’s electricity needs? Yes.
Tesla acquired SolarCity and has built utility-scale, commercial, and residential solar installations around the USA. Puerto Rico had electricity demand of roughly 20 TWh annually prior to Maria. That would require in the range of 11.4 GW of solar capacity, if solar were the only option. Puerto Rico already has both wind and solar farms with a combined capacity of about 340 MW. Wind has a higher capacity factor than solar all else being equal, so the combination generated about 2% of Puerto Rico’s demand in 2016.
SolarCity had an installed base of 2.45 GW of capacity when it was acquired by Tesla, so this is a stretch. Tesla has started production at its solar gigafactory in New York state. This, combined with ongoing purchases from absurdly larger-scale Chinese manufacturers, make the number of solar panels achievable. China installed 3 times the amount Puerto Rico would need in 2016 alone, but it’s China.
As someone pointed out recently, Puerto Rico is an island surrounded by water, so it’s easy to get the requisite solar panels there cheaply. Enough solar generation could be sourced and delivered. Installing it all would require imported labour to bolster the Puerto Ricans, but unions from the USA are already landing members to support the rebuilding, including the International Brotherhood of Electrical Workers. This does point to another challenge with replacing the existing structures, which is that unions would also have to agree with both the changes and the labour imports.
Is Puerto Rico well positioned for a strongly solar grid? Yes.
Puerto Rico is in the tropics. Among other things, this means relatively consistent duration of daylight. They don’t have to accommodate long winter nights and short days of generation. And solar energy generates electricity on all but the darkest of days. And the sun shines closer to straight down for much of the day. There are fewer shadows to deal with.
Is Tesla able to provide a mixture of building and grid storage sufficient to provide for all of Puerto Rico’s grid balancing needs with the solar? Eventually, yes.
Being in the tropics reduces the actual need for storage to a day of demand to achieve much greater resilience of electricity than they had prior to Hurricane Maria. After all, when Maria passed, the sun came out again. That amounts to about 55 GWh of battery storage.
Once again, that’s a big number, bigger than anything Tesla has done before. Its largest installation to date is 100 MWh and is only now closing in on completion. However, that ignores the cars. About 210,000 Teslas with an average of about 75 kWh of batteries make for about 16 GWh of batteries. Then there are the Powerwalls, which are a bit of a rounding error, but would be critical in the Puerto Rican context. With the Gigafactory, which will produce its batteries online and on track to achieve 35 GWh a year by end of 2018, including all car demand, this is obviously a limiting factor.
Unlike solar panels, there isn’t another source of Tesla’s grid and home storage that the company can leverage. Tesla is already one of the biggest producers in the world. And the output of the Gigafactory is expected to serve a massive number of new cars rolling off of the line as well as home and grid storage projects all over the world.
Would a solar and storage solution be more resilient in the event of another hurricane? Yes.
Tesla’s new solar tiles have been tested to be able to withstand massive hail better than alternative tiles do, meaning that they would also stand up to objects thrown by hurricane-force winds. Similarly, solar panels in general are typically designed to survive up to 140 mph (225 km/h) winds. And as many analysts including the Department of Energy have pointed out, grid resiliency is not increased by fossil fuels but by renewables.
That said, more has to be done to make solar farms in Puerto Rico capable of dealing with hurricane-force winds. Existing solar farms had minimal to extensive damage during Maria.
Then there are the Less Positive Indicators
Can Tesla have Puerto Rico rezone all necessary land for solar and storage? Maybe.
The island only has about 200 MW of solar energy at present, but that’s sufficient to have governmental thought put into regulation and zoning. Extending this based on emergency needs in the aftermath of Maria is possible. As has been noted, never waste a good crisis.
A megawatt of solar requires about 2.5 acres or one hectare of space. A fair amount of the generation will be on rooftops, but in order to build out solar capacity rapidly, a great deal of it will need to be at utility scale. A working ratio might be 1 MW rooftop to 4 MW utility scale. Puerto Rico already has net metering, so individuals can presumably deal with their requirements. But that suggests that about 23,000 acres or 9,000 hectares have to be set aside for solar generation. For context, that’s about 1% of Puerto Rico’s total land area. It’s significant but achievable.
However, there are existing territorial and extra-territorial actors who have been making a great deal of money off of the expensive fossil fuels previously used to provide 98% of the island’s 20 TWh annual electricity needs. They will be exerting fiscal pressure through all of their myriad channels to ensure that the current model persists and new models don’t emerge. If Musk and Tesla throw their weight behind making Puerto Rico a global case study, it’s likely that this won’t matter, but that likely depends on Musk actually focusing on this sufficiently to drive it forward.
Can Tesla have Puerto Rico institute building codes that are hurricane proof and would allow Tesla solar roofs to work effectively? Probably not.
As Hurricane Irma showed clearly, the right building codes mean that homes and buildings can survive hurricanes. But most homes in Puerto Rico are required to withstand less than Force 3 hurricanes. Ensuring that when homes are rebuilt they are to the new standards of 2011 or greater would mean that solar roofs would still be in place and able to generate electricity when storms pass.
Once again, there will be money and political will arrayed against this, along with competing priorities and an urgent timeline to rebuild basic shelter. Changing codes right now would increase the cost of replacing roofs lost during Maria and delay that process.
It’s certainly possible that individual buildings when rebuilt could be built to withstand another hurricane like Maria, but it’s not required today. And buildings with solar roofs that are built to current standards would suffer just as badly.
Are solar and storage alone a reasonable, efficient, and cost-effective solution for energy for Puerto Rico? No.
Solar by itself has limitations which require larger than necessary amounts of storage to achieve resilience. That’s true of almost any single form of generation. It’s much easier to have a mix of generation. A lot more wind farms would be excellent, targeting roughly the same annual generation from wind as from solar. A bit of biomass electrical generation, especially biomethane with a combined cycle gas plant, would be useful. A lot of demand management and efficiency work would be good. Some tidal and lee side wave energy wouldn’t go amiss. Trying to balance a complete grid with only storage and one type of generation would be foolish when there are alternatives.
