My First Week of Making Solar Electricity
In December 2025, we got a photovoltaic (PV) array installed on our roof. I was going to wait longer, but the 30 percent solar tax credit was going away at the end of 2025. We got in just under the…
solar energy
Can Clean Energy Eliminate All Rejected Energy?
To understand energy on a large scale in the US, you can't do better than studying the energy flow charts from the Lawrence Livermore National Lab (part of the US Department of Energy). In the 2023 version above, you see…
A BTU Is A BTU…Or Is It?
Since we're on the topic of energy, let's extend last week's discussion of electric resistance heat efficiency. I've sometimes told people that "a BTU is a BTU." (For the rest of the world, the conversion is simple: "A joule is…
Introduction to Whole-House Electricity Monitoring
Last year I bought the Emporia Vue whole-house electricity monitoring system.* This past weekend, I finally installed it. The photo below shows my electrical panel with the monitor installed. Yes, it looks like a mess at the moment. The panel…
Substituting Solar Panels for Insulation in the Energy Code
Supply and demand are two different things. When you think of an energy code, say the International Energy Conservation Code (IECC), you probably think of demand, not supply. Conserving energy, after all, means reducing demand. It's related to supply only…
The Cost of Solar Energy Keeps Dropping, But…
Solar energy has sex appeal. If you want to show the world you're doing something to reduce pollution, you put photovoltaic (PV) panels on your roof to generate clean electricity. Even better, you drive a plug-in hybrid or an all-electric…
Is Global Energy Use Getting Better?
Every day, I get updates on various energy data from the US Energy Information Administration (EIA). Earlier this week I got one showing the graph below, indicating that energy intensity for the whole world is going down. That's a good…
My Top 10 Energy Efficiency Articles and Ideas of 2015
The year 2015 is almost finished. I've written 69 articles here in the Energy Vanguard Blog. I've been to a bunch of conferences and talked to a lot of people. A lot of thoughts about building science, energy efficiency, indoor…
Electricity Demand and the Duck Curve
You may think there's no more boring topic than electric utilities. Power plants. Transmission lines. Engineers with flat top haircuts and pocket protectors full of pens in their white short-sleeved shirts. Well, let me say two words that might help…
Clarifying the Confusing Calculations for Zero Energy Buildings
A zero energy building is one that produces on-site at least as much energy as it uses. As I've written here before, the US Department of Energy has been mulling over the various ways to define and calculate zero energy…