I had two thoughts when I saw the picture of acres of solar panels that went along with the March 29 article "Order won't alter state's clean-energy path," which expands on the impacts of President Trump's environmental policies. The first is the dirty little secret about the mining of rare-earth metals. Open-pit mining and tailing ponds are used to extract the metals needed for solar cells. Ninety-seven percent of rare-earth mining occurs in China — so I guess it isn't our problem. We won't tolerate a nickel mine in our state, but it is OK to create waste radioactive tailing ponds in China. For every ton of usable rare-earth metals, one ton of radioactive waste is created, as well as a host of known carcinogenic toxins.

My second thought was "how many acres?" are no longer used for growing crops or reclaimed as prairie. On this point: While working on my graduate degree in general systems and cybernetics in the late 1970s, I studied using microwave transfer of energy from satellites in geosynchronous orbit to receiving stations on the ground. The receiving station for such a system looks much like the picture that accompanied the March 29 article, with one significant difference. The receiving microwave grid consists of metal plates with evenly spaced holes that allows sufficient light to grow grass. The land then becomes dual-use: energy collection, as in the solar cell method, but also as either grazing land, truck farms or returned back to natural prairie land.

The microwave solution does not use rare-earth metals in the receiving antenna. This solution was technically but not economically feasible in the late '70s. It is now 40 years later, and it is time to dust off this idea and give it a consideration. There is no free lunch, and every energy solution, with the exception of reducing world population (best long-term green solution), has its flaws. The major concern raised back in the '70s was impact on birds and airplanes. Both need to be evaluated, but it is a technology that at least has the promise to be much more eco-friendly than both wind and solar.

Michelle Hoffman, Mendota Heights

Hurts schools and students? Editorial was wrong about that.

In 1975, I had just finished my second year of being a St. Paul schoolteacher when I received a message saying that I, along with many other new teachers, would not be returning to that school the following school year. I am sure that I felt it was unjust, but I remember being told by a veteran teacher that laying off teachers according to seniority was the only fair way to do it. He was right for a number of reasons, the most important being that, due to salary schedules, experienced teachers can easily be paid twice as much as new teachers. Who do you think they are going to lay off? The Star Tribune points out in a March 28 editorial that it's "more difficult to attract and retain new teachers, if they know their positions will be the first on the chopping block when budget cuts occur." I would point out that new teachers would be easier to attract if they knew their jobs had some protection from biased administrative practices.

John Giese, St. Paul

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The editorial that argues against last in, first out (LIFO) is so wrong because it pits people against each other in many ways. It pits older workers against younger. It pits nonunionized workers against unionized. It pits workers not knowledgeable about what it is to work in education against those who are in education. It pits stressed taxpayers with and without children against stressed educators putting their best into the children they support and do great work for. It pits parents worried about their children's future in the marketplace against teachers who have not created the uncertain job market that causes the parents' worries.

Division serves to drive down the value people receive from public schools. It drives down the wages of all workers. It is bad for children, too. Their education is made worse as education unions are weakened. The work environment that children will inherit will have fewer chances for them to have jobs and careers that pay well.

People, do your homework and understand the history of division. As people are divided, there is less strength and well-being for all ordinary people. Those who divide will be the conquerors.

Paul Rozycki, Minneapolis

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When trying to tackle complex issues regarding teachers and schools, I think it prudent to acknowledge the volume of our collective conversation often goes "up to 11." Teachers have a very public profession that is talked about, analyzed, managed, praised and challenged by people with varied proximity to actual teachers and the students they teach. And yet, when discussing policies like "first in, last out," opinions mount, sides are drawn, the stakes are raised and decisions are made.

Teacher retention is a major issue facing our nation's schools. The Alliance for Excellent Education (AEE) found that about 13 percent of teachers change schools or change professions every year. This number amounts to roughly half a million teachers every year.

Research has shown that students do worse on standardized tests in reading and math in years when teacher turnover rates were high. In fact, it has been found that there is a disruptive impact of teacher turnover beyond changes to teacher quality. In other words, the act of teacher turnover has an adverse effect on schools regardless of the quality of teacher who leaves.

Before we decide on who should be fired first, maybe we should discuss why students, through no fault of their own, are the ones whose lives are affected the most when school budgets are decided.

Jeff Henning-Smith, Minneapolis

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I understand the dilemma that teacher seniority protections pose for students and for young professionals hoping to hold on to teaching jobs and career dreams. I agree that there are some "experienced" teachers who should or need to get out of the way so our children have the best teachers in their classrooms. Unfortunately, it is also clear that school administrators would use any weakening of tenure/seniority laws to solve budget issues.

It isn't uncommon to have a 20-year, veteran teacher with a master's degree making $20,000 to $30,000 more than a teacher just coming into the profession. I don't think any administrator would pause at finding a way to get that old, expensive teacher out the door and put that 30 grand back into the coffers. Districts take a hard-core, bottom-line business approach when it comes to staffing, and teacher effectiveness is frequently a judgment call that can turn on the whims of district administrators looking to pare their budgets.

Some districts currently motivate experienced teachers to retire by placing them in undesirable assignments — requiring them to teach in multiple schools, for example. This "best use" of their staff is an effective tool used to persuade older teachers to do the right thing. I would suggest that any loosening of seniority protections carry some kind of clause that says districts must be budget-neutral when replacing senior staff with less-experienced teachers. If these young teachers are that good, perhaps the districts should also compensate them with that departing senior staff's salary.

Terrance Olson, Minneapolis