Cooking based on solar powered batteries is the next frontier for renewable energy. Consider this: If India’s 275 million households and restaurants, street vendors, and tea-sellers were to use solar plus battery based cooking, the demand for batteries would amount to ~1,000 GWh.
Compare that to Tesla’s gigafactory for car batteries at 150 GWh, the expected final capacity post 2020. India therefore needs seven times the Li-ion battery capacity for cooking alone. Multiply this by at least four to estimate the global demand for batteries for cooking. Why then the fuss about gigafactories for electric cars? We are enamored by cars, yet daily cooking is a bigger market.
I assume induction cookstoves and Li-ion battery chemistries, and not variants of lead acid, because of performance and economics issues – weight, form factor, safety, power density, longevity — that make the latter less attractive.
Photovoltaics+Batteries for Cooking
The batteries may be charged using grid electricity, of course. But it would be better if they were charged using solar panels. Why?
One, grid electricity may power the induction cooktops — no battery necessary — but electricity is not reliably available in emerging economies for ~ 4 billion people. If we assume five hours of sunlight daily for most of India, charging the batteries — around 2.5 to 3 kWh each per household — would require 3 solar panels of ~ 200 Watts each.
Two, for street vendors, electricity outlets may not be easily accessible. Roam the streets of many cities, and kerosene and coal is used for cooking, tea-making, sandwiches, dosas, and other snack foods. Often, LPG cylinders are used too. But electricity use is notably absent.*
Three, in the US, for backyard cooking, at picnics, for RVs and boats too, electricity outlets may not be conveniently available; battery-based solutions would be easier.
Four, economics favors off-grid cooking. Grid electricity — based on fossil fuel burning, mainly coal, for over 50 percent of it — will continue to rise in price, while solar plus batteries will fall in price for the foreseeable future. For existing homes, there would be the capital cost of solar plus battery infrastructure. That fixed cost can be amortized over at least a decade with today’s Li-ion batteries, which are constantly falling in price as global volumes increase.
Metering? Why Bother
We measure electricity in kWh because there is a constant burning of a fossil fuel, as a flow of coal, LPG, kerosene, natural gas or some hydrocarbon at the generating end of the infrastructure, and is measured as such. Metering as kWh is unnecessary when there is no flow of a burning fuel.
Cooking may be viewed as an app, an icon on a smartphone. Its use may be measured, if at all, in meals cooked or hours of use. Just as “gigawatt” bundles has replaced “minutes” in telecom, so also meals cooked may replace kWh. We could parse out cooking use from grid electricity use, even in the industrialized world, if such a solution is cheaper, and allows local control.
Next generation cooking is clean, environmentally benign, and easy to use. In fact, with induction cooktops, there is neither fire nor flame. Cooking is also location independent; why cook at a particular place in the kitchen — the countertop — when the cookstove, lightweight and portable, can be moved to the living room or the dining table. One may cook while watching TV or supervising homework.
Economics of Cooking Relative to Automobiles
Consider 275 million household, small business, and restaurant equivalents in India, all cooking using solar+batteries. Each pays ~ Rs. 650/month, or $8.50/month for service, comparable to but less than the cost of a LPG cylinder at Rs. 750/month, or $11/month, and rising. This is a ~ $30+ billion/year revenue market, and $5+ billion a year is spent in importing LPG. The export bill can be reduced with a solar+battery solution.
Consider ~ 15/cars per thousand population in India. That is, roughly 20 million cars. Suppose all of them were electric at 25 kWh each. This yields 500 GWh, or half of battery storage needed for solar+battery based cooking.
The world is rightly focused on electric transport but we may not ignore solar+battery based cooking either. In recognition of the opportunity and the welfare it represents, our goal is to create an integrated solution — from solar panels to induction cookstove to induction-supported cookware, including pans and pressure cookers.